The invention is based on a method with the species of the dead-reckoning navigation, corrected by magnetic sensor and odometer signals.
In known location determination systems for vehicles, information regarding the respectively driven distance is derived from the revolution of the wheels, while in some systems a magnetic sensor detects the course and in other systems a measurement of the difference of the wheel revolutions detects the change of the course. Both methods have disadvantages. The magnetic sensor often experiences interference--for example because of steel structures close to the path of the vehicle or because of changes of the magnetic properties of the vehicle. Since errors in detecting path changes with the aid of wheel pulses accumulate in the course of driving the vehicle, large inaccuracies result with increasing length of the drive. But deviations of the course changes determined with the aid of the wheel pulses from the actual values occur for many reasons. For example, the diameters of the two wheels do not agree, or the effective axle width changes with the degree of turning and the load on the vehicle. Accordingly, differences in the wheel pulses already occur with straight-ahead driving, and the deviations during cornering are added.
A further difficulty in connection with the known systems lies in that the wheel sensors employed deliver a limited number of pulses per wheel revolution for reasons of cost and because of the severe operating conditions in the vehicle. It is therefore advantageous to use the sensors of an anti-locking system, for example, which only supply 96 pulses per wheel revolution.